Interrelationships between densitometric, geometric, and mechanical properties of rat femora: Inferences concerning mechanical regulation of bone modeling

Abstract

A compensation for differences in bone material quality by bone geometric properties in femora from two different strains of rats was previously shown by us. A feedback mechanism controlling the mechanical properties of the integrated bones was then proposed, in accordance with Frost's mechanostat theory. Evidence of such a system is now offered by the finding of a negative correlation between the modeling-dependent cross-sectional architecture (moment of inertia) and the mineral-dependent stiffness (elastic modulus) of bone material in the femoral diaphyses of 45 normal Wistar rats of different sexes, ages, and sizes. The strength and stiffness of the integrated diaphyses were found to depend on both cross-sectional inertia and body weight, not on bone mineral density. These findings are interpreted as supporting the hypothesis that the architectural efficiency of diaphyseal cross-sectional design resulting from the spatial orientation of bone modeling during growth is optimized as a function of the body weight-dependent bone strain history, within the constraints imposed by bone stiffness. Results suggest a modulating role of biomass, related to the system set point determination, and explain the usually observed lack of a direct correlation between mineral density and strength or stiffness of long bones in studies of geometrically inhomogeneous populations.

Effect of Zinc Level and Source (Zinc Oxide Vs. Zinc Glycine) on Bone Mechanical and Geometric Parameters, and Histomorphology in Male Ross 308 Broiler Chicken

“…A Zwick Z010 universal testing machine (Zwick GmbH & Company KG, Ulm, Germany), equipped with a measuring head (Zwick GmbH & Company KG, Ulm, Germany) with an operation range up to 10 kN, linked to a computer with test TestXpert II 3.1 software (Zwick GmbH & Company KG, Ulm, Germany) was used, as previously described (Tomaszewska et al, 2013;Tomaszewska et al, 2015). Maximum elastic strength and ultimate strength were determined as previously described (Ferretti et al, 1993;Tomaszewska et al, 2012).…”

“…Based on the measurements of the horizontal and vertical diameters of the mid-diaphyseal cross-section of the bones (data not shown), the cross-sectional area and mean relative wall thickness were derived (Ferretti et al, 1993). The cortical index of the bone was estimated as previously described (Tomaszewska et al, 2015).…”

Effect of sodium butyrate and Yucca schidigera extract on bone characteristics in growing pigs

“…Ultimate strength (Wf) of bones was measured by three-point bending test using an INSTRON 4302 apparatus (Instron Corp., USA) linked to a computer, registering the relationship between the perpendicular force acting to the longitudinal axis of the bone and the resulting displacement (6). The distance between supports was set at 40% of the bone length.…”

“…The distance between supports was set at 40% of the bone length. On the basis of vertical and horizontal diameters of the bone mid-shaft cross section, the geometrical parameters such as the cross-sectional area (A) and second moment of inertia (Ix) were determined as described previously (6).…”

Effect of HMB and 2-Ox administered during pregnancy on bone properties in primiparous and multiparous minks (Neivison vison)

“…The measuring head loaded bone samples with a constant speed of 10 mm/min. The maximum elastic strength (Wy) and the ultimate strength (Wf) were determined as described previously (7,26). On the basis of measurements of the horizontal and vertical diameters of the mid-diaphyseal cross-section of the bone, the cross-sectional area (A) and the mean relative wall thickness (MRWT) were calculated (7).…”